Preparation and characterization of aluminum borate whiskers reinforced ceramics with MnO2 addition

Ceramics with aluminum borate whiskers (ABWs) were prepared from H3BO3 and Al2O3 reagent, with and without 6 wt% MnO2 used as an addition. The microstructures, phase composition, and crystal structure of the ceramics were analyzed via scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The results show that MnO2 is an effective addition for enhancing the flexural strength of ceramics. The MnO2 could lead to the distortion of lattice, and improve the mechanical strength via a solid solution strengthening mechanism. Moreover, the content of H3BO3 and the sintering temperature were also key factors in the manufacture of optimal ceramics. The ceramic made from 6 wt% MnO2 addition, 25 wt% H3BO3, and sintered at 1200 degrees C, showed the highest flexural strength of 88.5 (+/- 1.9) MPa, and had a bulk density of 1.64 g/cm(3) and porosity of 44.2%.